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schwit1 writes "The competition heats up: For the first time in six months SpaceShipTwo completed a test flight [Tuesday]." The article linked is from NBC, which also has a deal with Virgin Galactic to televise the first commercial flight. It is thus in their interest to promote the spacecraft and company. The following two sentences from the article however clearly confirm every rumor we have heard about the ship in the past year, that they needed to replace or completely refit the engine and that the resulting thrust might not be enough to get the ship to 100 kilometers or 62 miles: "In January, SpaceShipTwo blasted off for a powered test and sailed through a follow-up glide flight, but then it went into the shop for rocket refitting. It's expected to go through a series of glide flights and powered flights that eventually rise beyond the boundary of outer space (50 miles or 100 kilometers in altitude, depending on who's counting)." Hopefully this test flight indicates that they have installed the new engine and are now beginning flight tests with equipment that will actually get the ship into space.

Oh so close to something truly cool--the 1 hour to Tokyo flight. Yeah, you'd have to be insanely rich to buy a ticket; but you already have to be insanely rich just to get into suborbital space on this thing. Don't get me wrong. The guys who put this together are fantastic. It's just that it seems like a little more effort could get you something so much more fantastic.

The difference between something able to reach 100km, and something able to reach that altitude with enough energy to make it a quarter of the way around the world, is significant. They are really not close at all to being a useful transportation mechanism.

According to the linked article this was a glide test, not even a powered one. Given the fact that SpaceShipTwo (a bit of a hyperbolic name - RocketPlane would be more accurate) has flown dozens of times, some of those powered, I don't get the "news" aspect exactly. Is it that they had stopped for a few months and it is "news" that they resumed? Still how does that translate to "competition heats up"? And when we say "competition", which other recreational high altitude planes are we talking about and how are they doing?

It's a solid rocket motor, of course it needs to be replaced after every flight.

Actually, it is a hybrid rocket motor [wikipedia.org] which has characteristics of both a solid and liquid motor. Wiki says they are changing the propellant [wikipedia.org] which would explain the motor replacement.

Notice how in one part of the summary, 100km is 62 miles. Then later it becomes 50 miles. Is this Lorentz-Fitzgerald contraction at work? If the summary had meandered on, would the ratio increase further?

Odd how L-F contraction only affects imperial measurements. Maybe Haldane was right, and the universe is indeed queerer than we can imagine.

I did notice one part of the summary where they converted 100 km to 62 miles, and another where they noted that different groups define the edge of space differently, with some using 100 km as the boundary and others using 50 miles. However, at no point did I note someone trying to equate 100 km to 50 miles. Can you point it out for me?

The U.S. defines the edge of space as 50 miles (80 km), the rest of the world as 100 km. The discrepancy comes from the fact that it is a somewhat arbitrary boundary so both chose a round number in their respective measurement system. The two values are however reasonably close. For details: https://en.wikipedia.org/wiki/... [wikipedia.org] .